IP address and SEO

Question

I currently host 5 websites within a dedicated server I own.

I have several questions:

1. Does it matter if I host all my sites on 100.100.100.100 (the server's IP for example) or if I split them into 100.100.100.100, 100.100.100.101 ... 100.100.100.104 (that is, each site on its own IP).
2. Does it matter if I use a C-Class for each website? Do search engines really care if your site has its own c-class?
3. Do search engines penalize a website if it moves its IP?

Thanks,

Joel